My tinfoil hat has melted - I've misplaced my glasses and am typing with my nose glued to the screen. But there's so much.
Basically, from what I've been able to read (paper abstracts here and there) - Iodine AND Selenium play a crucial role - together!
And one other thing, a quick googling exercise as to foods increase glutathione levels reveals.... asparagus, avocados, broccoli, TURMERIC,... and SELENIUM (the page is protected, I found out after trying to copy the text to paste here for 15 minutes)